Indirect calorimetry is used to study the metabolic demands active tumors have on cancer patients. A rigid lucite head canopy with a controlled air flow rate, an on line mass spectrometer and a computerized data processing system will be utilized. Stable isotopes will be used to measure whole body protein turnover and muscle and tumor fractional synthesis rates. Primary objectives are to determine if resting energy expenditure glucose oxidation, whole body protein turnover and K40 levels are different from controls in preoperative sarcoma patients. Of further interest is whether these parameters correlated with tumor size or protein fractional synthesis. The value of these parameters will again be measured after resection of the tumor.